How to return data from temporary activity opened in a fragment-CodePudding

Basically I have a MainActivity which contains 3 different fragments, and within one of those fragments I can click a button that opens a new activity with a simple RadioGroup choice, and whenever I click on one of the options, it automatically closes the activity. Now, my problem is transfering that selected data to the fragment, so I can update it depending on which RadioButton I chose.

The closest I have come to a solution for this is startActivityForResult, but it seems that is no longer working...

CodePudding user response：

You can use SharedPreferences to save the state of the radio buttons, or you can create a callback function that triggers the main activity when you dispose the fragment and pass as parameter the state of the radio buttons.

CodePudding user response：

From official guide doc:

In your fragment, create & register a launcher

private val launcher = registerForActivityResult(
    ActivityResultContracts.StartActivityForResult()
) { result: ActivityResult ->
    handleResult(result)
}

Create a method to handle ActivityResult:

fun handleResult(result: ActivityResult) {

    // Handle the returned result as you do in onActivityResult()
    // Use result.resultCode to determine OK or Cancelled result

    if (result.resultCode == Activity.RESULT_OK) {
        val resultIntent = result.data
        // Use returned Intent
    }
}

Launch the OtherActivity for result like this:

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    // ...

    val selectButton = findViewById<Button>(R.id.select_button)

    selectButton.setOnClickListener {
        // Launch activity from whom you want the result
        val intent = Intent(requireContext(), OtherActivity::class.java)
        launcher.launch(intent)
    }
}

In the OtherActivity, when you're ready to send back result, create an intent and put the data in it.

val intent = Intent()
intent.putExtra("YOUR_KEY", YOUR_DATA_HERE)
setResult(Activity.RESULT_OK, intent)
finish()

After this, you will get result in handleResult() method.